Flex-snubber

ABSTRACT

In a cartridge for use in a motion picture camera, a frustoconical snubber is mounted on a resilient, deflectable stem and is positioned along a film path in the cartridge. As the film is intermittently advanced through the cartridge in contact with the snubber, the snubber is resiliently deflected to increase the surface area of the snubber engaged by the film. The deflection of the snubber and the increased frictional forces between the film and snubber resulting therefrom dampen variations in tension forces along the film permitting more accurate registration of the film for recording of images thereon.

United States Patent Bradford et al'.

154] FLEX-SNUBBER [72] lnventors; James C. Bradford; Stephen H.

Miller; Jeffrey C. Robertson, all of Rochester, N.Y.

[73] Assignee: Eastman Kodak Rochester, N.Y.

22 Filed: Nov. 24, 1971 [21] App1.No.: 201,825

Company,

[52] US. Cl. 3242/19 4, 226/189, 226/198,

242/76, 242/197, 352/156 [51] Int. Cl. ..G03b1/04, G1 lb 15/32 [58] Field of Search ..242/194-206, 76;

[56] References Cited 1 UNITED STATES PATENTS Foster ..242/199 Edwards et al. ..242/194 [151 3,700,188 [451 Och/24,1972

8/1966 Williams ..242/194 3,312,412 4/1967 -Mueller ..242/71.2 3,334,835 8/1967 Kaneko .,....242/71.2 3,424,391 1/1969 Di Veto ..242/76 X Primary Examiner-Leonard D. Christian Attorney- -W. H. J. Kline et all 57 1 ABSTRACT In a cartridge for use in a motion picture camera, a frusto -con-ical snubber is mounted on a resilient, deflectable stem and is positioned along a film path in the cartridge. As the film is intermittently advanced through the cartridge in contact with thesnubber, the snubber is resiliently deflected to increase the surface area of the snubber engaged by the film. The deflection of the snubber and the increased frictional forces between the film and snubber resulting therefrom dampen variations in tension forces along the film permitting more accurate registration of the film for recording of images thereon 11 Claims, 4 Drawing Figures PATENTEDucI 241912 3. 700. 188

JAMES C. BRADFORD STEPHEN H. MILLER JEFFREY C. ROBERT SQN INVENTORS aw/M 6% 9.949%

AT TORNE YS FLEX-SNUBBER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to guide means for controlling and directing flexible strip material. More specifically, this invention relates to a resilient flex-snubber for a flexible strip of recording material (such as film) in a cartridge.

2. Description of the Prior Art Cartridges for use in cinematographic and other recording apparatus are generally well known in the art. Typically, such cartridges provide for movement of a tape or strip of recording material along a predeten mined path leading from a supply chamber to arecording or reproduction aperture, and then into a take-up chamber. Accurately controlled movement of the strip along such a path, especially in the region of the recording or reproduction aperture, is essential to assure desired registration characteristics.

To smooth undesired movement of a strip material, it is known in the art to provide what is commonly referred to genericallyas a snubber. The term snubber has been used in reference to almost any surface which contacts a strip material to reduce sudden surging movements, suppress undesired movement or otherwise smooth the movement of the strip.

Prior art snubbers are of a variety of constructions depending upon the ultimate purpose they are to fulfill. One type of snubber known to the art is illustrated in commonly assigned US. Pat. No. 3,208,686 issued Sept. 28, 1965, in the name of E. A. Edwards et al. which shows a fixed snubbing surface that is effective to guide a flexible film strip. As shown therein at 50, 54 and 57, fixed snubbing surfaces may be generally cylindrical or cylindrical with a conical extension and cooperate with other cartridge elements to compensate for different types of movement imparted to the filmstrip along the film path. The snubbing surfaces as disclosed in that patent control film guiding and film tension for smooth movement of the film during operation of the cartridge.

sued to E. S. Porter on June 20, 1939. As disclosed therein, a flat spring or roller along the film path in a film magazine provides the desired snubbing action. Other snubbers of this general type are disclosed in US. Pat. No. 2,173,996 issued to H. Becker, on Sept. 26, I939, and US. Pat. No. 2,287,792 issued to 'W. D. Foster on June 30, 1942. I

Briefly, some of the aforementioned snubbers have been used in a cartridge of the type generally disclosed by the aforementioned Edwards et al patent, such being commonly referred to as a super 8 cartridge. When a super 8 cartridge is properly inserted into a motion picture camera designed to receive the cartridge, a film advancing claw in the camera can intermittently engage the film and advance the film from a supply chamber in the cartridge along a film path and into an exposure aperture. Simultaneously, a take-up drive in the camera rotates the core of the take-up reel to wind the film in a cartridge take-up chamber which is coaxial with the supply chamber. With more conventional film the prior art snubbers have been effective to isolate the portions of the film at the supply coil, the take-up roll tional cameras during advancement of film at conventional rates (e.g., 18 frames per second). In operation of such a cartridge loaded with thin-base films, the intermittent forces imparted to the flm by the film advancing claw of the camera overcome the inertia and frictional forces of the film in the cartridge in an undesirable manner resulting in unsatisfactory performance of the cartridge. Rather than drastically alter the structure of commercially accepted cartridges or cinematographic apparatus to solve the problem Another common type of snubber isdisclosedin commonly assigned US. Pat. No. 3,451,732 issued June 24, 1969, in the name of A. J. Tucker. The Tucker patent discloses a generally cylindrical roller which freely rotates about the axis of a post, the snubber serving not only to guide a film strip but also to snub undesired erratic motion that may be transmitted along the length of the film strip due to intermittant operations affecting the movement of the strip material. The rotatable snubber is effective where low frictional forces are desired and/or where the strip material is directed along an abruptly curved path. This type of snubber is also shown at 48 in the Edwards et al. patent. Rotatable guide members having surface shapes other than cylindrical are also known as disclosed, for example, in US. Pat. No. 3,334,835 issued to Keezi Kaneko on Aug. 8, 1967.

Another common type of movable snubber is one having a contact surfa e positioned along the path of the strip material and resiliently biased toward the strip. There are numerous snubbers of this type, but they may be generally described as having flat or cylindrical contact surfaces which are supported by resilient means. See, for example, U.S. Pat. No. 2,163,179 iscreated by such thin films, it is desirable to modify such cartridges in a way which will make them suitable for such film, and preferably in a way which will permit the cartridges to be loaded with more conventional films having greater thickness (e.g., about 4 to 5 mils thick).

SUMMARY OF THE INVENTION It is an object of the invention to provide an improved cartridge for use with flexible strip material, especially thin-base film strips that are to be intermittently advanced by a camera mechanism.

Another object of the invention is to provide a'cartridge in which forces created in a strip material by intermittent movement may be dampened, thereby resulting in smoothed movement of the strip material.

A further object of the invention is to provide a flexsnubber for use with a film strip for reducing undesired surges in tension in the strip due to intermittent advancing of the film strip at normal filming rates.

Still another object of the invention is to provide a flex-snubber for dampening surges in a strip by increasing the surface area of the flex-snubber that contacts the strip surface when the strip material exerts a force sufficient to deflect the flex-snubber.

In accordance with a preferred embodiment, a flexsnubber is placed in a cartridge for film or the like. The flex-snubber has a frusto-conical member and a resilient, flexible stem extending from the member. The end of the stem remote from the member is connected to the cartridge for resiliently mounting the surface of the frusto-conical member so that it -is engageable by the strip material. Also, the stem is deflectable in response to tension forces in the material from l a first condition wherein a first surface area of the member is contacted by the material toward (2 a second condition wherein a second surface area is contacted by said material. The stem, when flexed by the tension forces in the strip, exerts a biasing force urging the member from its second condition toward its first condition. The biasing force of the stem and change in friction forces between the material and the surface of the member dampen the tension forces and smooth the movement of the material relative to the cartridge.

The invention, and its objects and advantages, will become more apparent in the detailed description of the preferred embodiment presented below.

BRIEF DESCRIPTION OF THE DRAWINGS In the detailed description of the preferred embodiments of the invention presented below, reference is made to the accompanying drawings, in which:

FIG. 1 is a perspective view, partially broken away, of a preferred embodiment of a flex-snubber according to the invention and illustrating the position of the flexsnubber in a motion picture cartridge;

FIG. 2 is' an enlarged, fragmentary side view of the FIG. 1 flex-snubber, showing a position of the flexsnubber relative to the cartridge and film (shown in phantom) when the film and the flex-snubber are at a normal rest position;

FIG. 3 is a view similar to FIG. 2 but showing the position of the flex-snubber relative to the cartridge and film when the film is under tension force and the flex-snubber is substantially fully deflected; and

FIG. 4 is a fragmentary, sectional view taken along line 44 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Because snubbers, cartridges and related apparatus are well known, the following description is directed in particular to those elements forming, or cooperating directly with, the present invention, elements that are not specifically shown or described herein being understood to be selectable from those known in the art.

As previously indicated, the present invention relates to an improvement in film cartridges such as disclosed in the aforementioned commonly-assigned US. Pat No. 3,208,686, issued Sept. 28, 1965, in the name of Edwards et al. Accordingly, the complete disclosure in that patent is incorporated herein by reference. In the following description, numerals less than 100 are used to identify the same or similar parts disclosed in the Edwards et al. patent, and numerals greater than 100 are used to identify features not disclosed therein.

Referring now to the drawings, FIG. 1 shows a film cartridge generally designated which is generally of the type disclosed by Edwards et al. Cartridge 10 comprises a body 12 and a cover 14. Body 12 includes a cylindrical film supply chamber 28 and a cylindrical take-up chamber (not shown) separated by a wall 32. The chambers are at opposite sides of the body substantially in coaxial alignment with each other. A stationary locating boss or post 36 is formed integral with wall 32 substantially at its center and projects into supply chamber 28.

A coreless roll or coil 44 of film strip 46 is placed in supply chamber 28 coaxial to a boss 36 such that one spirally wound edge lies against the flat tray portion of an anti-friction disk (not shown) that rests on wall 32. The other spirally wound edge of the roll lies in a plane substantially parallel to and closely adjacent to the inner surface of wall 20 of the cover 14. By means of this positioning, the spirally wound convolutions of the coil are prevented from being displaced axially of the roll relative to one another by an amount which might cause jamming of the film strip in supply chamber 28 or otherwise adversely affect operation of the cartridge.

Film strip 46, as it is tangentially unwound from roll 44 and withdrawn from chamber 28, is threaded around aflex-snubber 148 of this invention and then along a film path which brings the film into registry with an exposure aperture 24 in wall 22. Suitable guide means in the cartridge, including guide members 150a and 150b, define the path for film through the cartridge. As film strip 46 is guided from the supply chamber 28 around the flex-snubber 148, it substantially reverses its direction so that tension forces in the portions of the web located on opposite sides of snubber 148 during unwinding of film from roll 44 are exerted in substantially parallel directions. As film leaves snubber 148 it is guided through a passageway formed beneath the inner surface of an edge wall 16 and canted so that the film is brought into alignment with the exposure aperture 24. Film strip 46 is then guided into the take-up chamber where it is wound upon a take-up core (not shown).

In the illustrated preferred embodiment of the present invention, flex-snubber 148 comprises a hollow head portion 149 having an exterior frusto-conical contact surface 151. Thus surface 151 has a relatively large end portion 151a (the top portion in FIGS. 2 and 3) and a relatively smaller end portion 151b. The head portion is supported by and preferably integral with a resiliently flexible stem portion 153. The stem portion projects from the center of the hollow head portion to form an annular recess 155 in the head portion. Stem portion 153 is anchored securely to a support boss 157 extending from wall 32 (as shown) or stem portion 153 can be secured to wall 32 directly. In either case, the stem portion is non-rotatably supported by the cartridge. This mounting fixes the stem portion axially and therefore normally maintains surface 151 angularly inclined to the film path, and also provides the desired resiliency or flexing of the stem in response to tension forces in the film portions adjacent the snubber as described in more detail later.

Flex-snubber 148 is so structured that the portion 151a of the frusto-conical surface having the larger dimension is at the end thereof opposite from the end of the stem portion that projects from the head portion, i.e., it is opposed to where stem portion 153 is attached to base 157. This provides a desirable snubbing effect upon film 46 which is curved around the frusto-conical contact surface 151 as explained in more detail later.

When film 46 is not under tension and flex-snubber 148 is in a normal rest position (FIGS. 1, 2 and 4), film 46 engages only part of the portion 151a of contact sur' face 149, i.e., along a line or band at the upper edge of the head portion. As shown in FIG. 2, surface portion 1510 is so positioned relative to film 46 that one side edge of the film contacts surface portion 151a.

When tension force is applied to the portion of the film 46 around the snubber, the head portion 149 is arcuately deflected due to the resultant force applied to the contact surface by the film which causes the stem portion to flex. When tension'forces applied to film 46 are relatively large, flex-snubber 148 will be deflected into the position shown in FIG. 3 wherein substantially the full width of the surface 151 is engageable with the surface of film 46. The deflection caused by the tension forces in film 46 is in opposition to the biasing force exerted by resilient stem 153 attempting to return to its normal position and the resilient biasing force serves to dampen the surges or variations in the tension forces. This in turn allows more accurate registration of film 46 for recording of images thereon. Also, increased surface contact between the film 46 and the frustoconical surface 151 when flexO-snubber 148 is deflected increases the forces required to move the film through the exposure aperture. The increased advance forces required eliminates streaming images which are characteristic'of low advance forces. Thus the use of flex-snubber 148 in the. cartridge allows for smoother movement and better control of the film 46 in the cartridge.

Operation of the invention will now be described in detail. Assume initially that cartridge is loaded into cinematographic apparatus having a claw and drive member (not shown) that are operatively coupled to the film and cartridge take-up member, respectively, for the purpose of moving film past exposure aperture 24 from supply chamber 28 to the take-up chamber. As the film strip 46 is intermittently pulled from roll 44 in supply chamber 28 by the pull-down claw, the roll will rotate about its axis on boss 36. As this occurs, a tension force is intermittently applied to the film by the film claw, and the inertia of the supply coil (being at rest) will be overcome and the supply coil will begin to rotate. This allows the outer convolution of film to pass tangentially from the roll and along its path about flexsnubber 148. Impulses or surges in tension imparted to the film strip 46 by the pull-down claw causes deflection of flex-snubber 148 toward its FIG. 3 position and are at least partially absorbed by the deflection of the snubber. Also, the deflection of the snubber results in increased frictional surface contact area between the film and the snubber due to the frusto-conical shape of the snubber surface 151 and its position with respect to the film path. This friction and the flexing of the snubber dampens the tension forces in the film strip and causes the supply roll to experience a more uniform force and unwind more smoothly. This substantially prevents the transmission of instantaneous tension forces to the film roll of a magnitude sufficient to cause the roll to unwind more than enough to supply a length of film substantially equal to the length of film advanced by the claw. In other words, it substantially prevents uncontrolled spilling of film from the film roll. Of course, it is to be understood that the friction between the film and the snubber is one factor affecting performance of the snubber. In this regard, a snubber molded from polyurethane materials has been found satisfactory.

Energy stored in the snubber stem due to flexing of the snubber toward the FIG. 3 position acts on the film and tends to pull film from the roll until the snubber returns to its FIG. 2 (rest) position. The snubber may or may not return to its FIG. 2 position before the film is advanced again by the claw, such depending (in part) on the frequency of operation of the claw.

It should be noted that it is not necessary for all portions of the contact surface 151 to be of the same configuration, i.e., only that portion of such surface that is engageable with the strip material should be frustoconical. However, in the preferred embodiment, the entire contact surface 151 is generally frusto-c'onical in shape in order to simplify manufacture of the snubber and its assembly into the cartridge.

While the invention has been particularly described I with reference to a film cartridge, the invention may I also be used in other flexible strip handling apparatus wherein a web is moved from a supply means to a takeup means.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. A cartridge for flexible strip material, said cartridge comprising:

a plurality of walls defining a chamber for strip material;

means within the cartridge defining a path for said material, said path defining means having a portion communicating with the chamber;

a snubber surface located along the path and engageable by strip material in the cartridge as such material is moved relative to the cartridge; and

means supported by said walls for resiliently mounting said snubber surface so that said surface is deflectable in response to tension forces in the material from (I) a first condition wherein a first area of said surface is contacted by said material toward (2) a second condition wherein a second and different area of said surface is contacted by said material, whereby the friction between the material and said surface is a function of the tension in the material.

2. A cartridge as set forth in claim 1 wherein said mounting means comprises a flexible stem supported by one of said walls.

3. A cartridge as set forth in claim 1 wherein said snubber surface when in its first condition is at an acute angle with respect to said path, and said surface when deflected to its second condition being engageable throughout substantially the entire width by said strip material.

4. A cartridge as set forth in claim 3 wherein said snubber surface is substantially frusto-conical in shape.

5. A cartridge as set forth in claim 4 wherein said mounting means comprises a flexible stem nonrotatably supported by one of said walls, said stem being substantially coaxial with said frusto-conical surface when said surface is in its first condition, said stern being flexed in response to tension forces acting against said surface to permit said surface to move from its first condition toward its second condition, and said stem urging said surface from its second condition toward its first condition.

6. A cartridge for flexible strip material, said cartridge comprising:

a plurality of walls;

means within the cartridge defining a path for said material;

a snubber comprising a member having a frusto-conical surface located along the path so that the surface is engageable by strip material in the cartridge as such material is moved relative to the path;

a resilient stem non-rotatably secured to said member and substantially coaxial therewith, the stem being non-rotatably secured to one of said walls so that said stem is flexed in response to tension forces in the material to permit said surface to move from (1) a first condition wherein a relatively small first area of said surface is contacted by said material toward (2) a second condition wherein a relatively large second area of said surface is contacted by said material, and said stem when flexed exerting a biasing force urging said surface from its second condition toward its first condition, whereby the biasing force and increased friction between the material and the surface serves to dampen tension forces applied to the strip material and smooth movement of said strip material relative to the cartridge.

7. In a cartridge for flexible strip material, said cartridge comprising a plurality of walls and means defining a path for said flexible strip material between portions of the cartridge, the improvement comprising:

snubber means comprising a member having a frusto-conical shaped surface positioned along the path; and

a resilient stem secured to said member and supported by one of said walls, whereby the stem can flex when strip material is drawn against said surface so that surges of tension forces in said strip material are dampened and movement of the strip material along the path is dampened.

8. In a cartridge for use in cinematographic apparatus, said cartridge comprising a plurality of walls defining a take-up chamber and a supply chamber for a roll of flexible film, said cartridge having means defining a path for the film leading from said supply chamber toward said take-up chamber, the improvement comprising:

resilient guide means for directing said film along said path, said guide means comprising a frustoconical shaped member and a flexible stern fixedly secured to said member and to one of said walls 0 the cartridge.

9. The improvement as set forth in claim 8 wherein said frusto-conical member is integral with said flexible stem, said frusto-conical member has a relatively small end portion and a relatively large end portion, and said flexible stem extends from said small end portion of said frusto-conical member and is substantially coaxial therewith.

10. The improvement as set forth in claim 9 wherein a flexible stem is secured to said one of said walls so that the portion of the surface of said frusto-comcal member which is along said path can be deflected between a first position wherein the surface is inclined relative to the path and a second position wherein such portion of said frusto-conical member is substantially aligned with said path.

, 11. A snubber for use with a cartridge for film or the like, the snubber comprising:

a frusto-conical member having a relatively small end portion and a relatively large end portion; and a resilient stern integral with and extending from said small end portion of said frusto-conical member, a portion of said stem remote from said member being connectable to a cartridge, whereby the snubber can be deflected when subjected to a force applied to the surface of said frusto-conical member. 

1. A cartridge for flexible strip material, said cartridge comprising: a plurality of walls defining a chamber for strip material; means within the cartridge defining a path for said material, said path defining means having a portion communicating with the chamber; a snubber surface located along the path and engageable by strip material in the cartridge as such material is moved relative to the cartridge; and means supported by said walls for resiliently mounting said snubber surface so that said surface is deflectable in response to tension forces in the material from (1) a first condition wherein a first area of said surface is contacted by said material toward (2) a second condition wherein a second and different area of said surface is contacted by said material, whereby the friction between the material and said surface is a function of the tension in the material.
 2. A cartridge as set forth in claim 1 wherein said mounting means comprises a flexible stem supported by one of said walls.
 3. A cartridge as set forth in claim 1 wherein said snubber surface when in its first condition is at an acute angle with respect to said path, and said surface when deflected to its second condition being engageable throughout substantially the entire width by said strip material.
 4. A cartridge as set forth in claim 3 wherein said snubber surface is substantially frusto-conical in shape.
 5. A cartridge as set forth in claim 4 wherein said mounting means comprises a flexible stem non-rotatably supported by one of said walls, said stem being substantially coaxial with said frusto-conical surface when said surface is in its first condition, said stem being flexed in response to tension forces acting against said surface to permit said surface to move from its first condition toward its second condition, and said stem urging said surface from its second condition toward its first condition.
 6. A cartridge for flexible strip material, said cartridge comprising: a plurality of walls; means within the cartridge defining a path for said material; a snubber comprising a member having a frusto-conical surface located along the path so that the surface is engageable by strip material in the cartridge as such material is moved relative to the path; a resilient stem non-rotatably secured to said member and substantially coaxial therewith, the stem being non-rotatably secured to one of said walls so that said stem is flexed in response to tension forces in the material to permit said surface to move from (1) a first condition wherein a relatively small first area of said surface is contacted by said material toward (2) a second condition wherein a relatively large second area of said surface is contacted by said material, and said stem when flexed exerting a biasing force urging said surface from its second condition toward its first condition, whereby the biasing force and increased friction between the material and the surface serves to dampen tension forces applied to the strip material and smooth movement of said strip material relative to the cartridge.
 7. In a cartridge for flexible strip material, said cartridge comprising a plurality of walls and means defining a path for said flexible strip material between portions of the cartridge, the improvement comprising: snubber means comprising a member having a frusto-conical shaped surface positioned along the path; and a resilient stem secured to said member and supported by one of said walls, whereby the stem can flex when strip material is drawn against said surface so that surges of tension forces in said strip material are dampened and movement of the strip material along the path is dampened.
 8. In a cartridge for use in cinematographic apparatus, said cartridge comprising a plurality of walls defining a take-up chamber and a supply chamber for a roll of flexible film, said cartridge having means defining a path for the film leading from said supply chamber toward said take-up chamber, the improvement comprising: resiliEnt guide means for directing said film along said path, said guide means comprising a frusto-conical shaped member and a flexible stem fixedly secured to said member and to one of said walls of the cartridge.
 9. The improvement as set forth in claim 8 wherein said frusto-conical member is integral with said flexible stem, said frusto-conical member has a relatively small end portion and a relatively large end portion, and said flexible stem extends from said small end portion of said frusto-conical member and is substantially coaxial therewith.
 10. The improvement as set forth in claim 9 wherein a flexible stem is secured to said one of said walls so that the portion of the surface of said frusto-conical member which is along said path can be deflected between a first position wherein the surface is inclined relative to the path and a second position wherein such portion of said frusto-conical member is substantially aligned with said path.
 11. A snubber for use with a cartridge for film or the like, the snubber comprising: a frusto-conical member having a relatively small end portion and a relatively large end portion; and a resilient stem integral with and extending from said small end portion of said frusto-conical member, a portion of said stem remote from said member being connectable to a cartridge, whereby the snubber can be deflected when subjected to a force applied to the surface of said frusto-conical member. 